Hmmmm interesting 🤔

It would probably be useful for someone who was consolidating, didn't want to spend more than they had to but also didn't want their signed Tx "lost".

A second layer mempool of sorts.

For me, I'd be using it because I wanted to push multiple Txs through (eg channel maintenance). The current functionality achieves this.

If I wanted to consolidate UTxOs I'd probably just send the Txs through at 5sats/vB & take my chances. Having them signed & unbroadcasted would have benefit of being able to just delete & replace them should you change your mind/preferences.